What a tub to shower conversion actually involves
The tub comes out, the drain is adapted, a new waterproofed pan is built to Tile Council of North America detail, and the walls are tiled to height. Because the footprint is often unchanged, the plumbing rough-in is usually modest. Where it grows is if you want the opening widened or the shower to take space from a linen closet.
Keep at least one tub
Worth thinking about before you convert every bathroom in the house. Buyers with small children look for a bath somewhere, and a house with none can narrow the market. Converting the primary and leaving the guest bath as a tub is the usual compromise.
Do it once, for later
If you intend to stay in the house, this is the moment to consider a curbless entry and blocking for grab bars. Both are inexpensive now and disruptive later. See aging-in-place remodeling.